Experiments were conducted at room temperatures, in an immobilized annular tube reactor, using titanium dioxide as the photocatalyst, to identify the influence of important operational parameters, viz., catalyst load (5-20 g m-2), benzene concentration (0.2-6 g m-3) and flow rate (0.2-1 L min-1) on the removal of benzene. Removal efficiencies for benzene ranged from 7% to 96% depending on the range of levels of these process parameters. A modified Langmuir-Hinshelwood (L−H) kinetic model has been suggested based on the experimental observations. The use of a combined plug-flow type L−H kinetic model yielded a design equation that can be used as the basis for the photoreactor scale-up as well as to find the mass transfer and reaction resistances in the photoreactor. The ratio of reaction rate resistance to the overall resistance was found to play an important role in establishing the predominant resistances between mass transfer and reaction rate occurring in the photoreactor.